Buggy code:
class DefaultIndexSettings { private DefaultIndexSettings ( ) { } static Builder defaults ( ) { <START_BUG> return ImmutableSettings . builder ( ) . put ( SETTING_NUMBER_OF_SHARDS , 1 ) . put ( SETTING_NUMBER_OF_REPLICAS , 0 ) . put ( "index.refresh_interval" , "30s" ) . put ( "index.mapper.dynamic" , false ) . put ( "index.analysis.analyzer.sortable.type" , "custom" ) . put ( "index.analysis.analyzer.sortable.tokenizer" , "keyword" ) . putArray ( "index.analysis.analyzer.sortable.filter" , "trim" , "lowercase" ) . put ( "index.analysis.analyzer.index_grams.type" , "custom" ) . put ( "index.analysis.analyzer.index_grams.tokenizer" , "whitespace" ) . putArray ( "index.analysis.analyzer.index_grams.filter" , "trim" , "lowercase" , "gram_filter" ) . put ( "index.analysis.analyzer.search_grams.type" , "custom" ) . put ( "index.analysis.analyzer.search_grams.tokenizer" , "whitespace" ) . putArray ( "index.analysis.analyzer.search_grams.filter" , "trim" , "lowercase" ) . put ( "index.analysis.analyzer.index_words.type" , "custom" ) . put ( "index.analysis.analyzer.index_words.tokenizer" , "standard" ) . putArray ( "index.analysis.analyzer.index_words.filter" , "standard" , "word_filter" , "lowercase" , "stop" , "asciifolding" , "porter_stem" ) . put ( "index.analysis.analyzer.search_words.type" , "custom" ) . put ( "index.analysis.analyzer.search_words.tokenizer" , "standard" ) . putArray ( "index.analysis.analyzer.search_words.filter" , "standard" , "lowercase" , "stop" , "asciifolding" , "porter_stem" ) . put ( "index.analysis.filter.gram_filter.type" , "edgeNGram" ) . put ( "index.analysis.filter.gram_filter.min_gram" , 2 ) . put ( "index.analysis.filter.gram_filter.max_gram" , 15 ) . putArray ( "index.analysis.filter.gram_filter.token_chars" , "letter" , "digit" , "punctuation" , "symbol" ) . put ( "index.analysis.filter.word_filter.type" , "word_delimiter" ) . put ( "index.analysis.filter.word_filter.generate_word_parts" , true ) . put ( "index.analysis.filter.word_filter.catenate_words" , true ) . put ( "index.analysis.filter.word_filter.catenate_numbers" , true ) . put ( "index.analysis.filter.word_filter.catenate_all" , true ) . put ( "index.analysis.filter.word_filter.split_on_case_change" , true ) . put ( "index.analysis.filter.word_filter.preserve_original" , true ) . put ( "index.analysis.filter.word_filter.split_on_numerics" , true ) . put ( "index.analysis.filter.word_filter.stem_english_possessive" , true ) . put ( "index.analysis.analyzer.path_analyzer.type" , "custom" ) . put ( "index.analysis.analyzer.path_analyzer.tokenizer" , "path_hierarchy" ) . put ( "index.analysis.tokenizer.dot_tokenizer.type" , "pattern" ) . put ( "index.analysis.tokenizer.dot_tokenizer.pattern" , "\\." ) . put ( "index.analysis.analyzer.uuid_analyzer.type" , "custom" ) . putArray ( "index.analysis.analyzer.uuid_analyzer.filter" , "trim" , "lowercase" ) . put ( "index.analysis.analyzer.uuid_analyzer.tokenizer" , "dot_tokenizer" ) ; <END_BUG> } }

Fix:
return ImmutableSettings . builder ( ) . put ( SETTING_NUMBER_OF_SHARDS , 1 ) . put ( SETTING_NUMBER_OF_REPLICAS , 0 ) . put ( "index.refresh_interval" , "30s" ) . put ( "index.mapper.dynamic" , false ) . put ( "index.analysis.analyzer.sortable.type" , "custom" ) . put ( "index.analysis.analyzer.sortable.tokenizer" , "keyword" ) . putArray ( "index.analysis.analyzer.sortable.filter" , "trim" , "lowercase" ) . put ( "index.analysis.analyzer.index_grams.type" , "custom" ) . put ( "index.analysis.analyzer.index_grams.tokenizer" , "whitespace" ) . putArray ( "index.analysis.analyzer.index_grams.filter" , "trim" , "lowercase" , "gram_filter" ) . put ( "index.analysis.analyzer.search_grams.type" , "custom" ) . put ( "index.analysis.analyzer.search_grams.tokenizer" , "whitespace" ) . putArray ( "index.analysis.analyzer.search_grams.filter" , "trim" , "lowercase" ) . put ( "index.analysis.analyzer.index_words.type" , "custom" ) . put ( "index.analysis.analyzer.index_words.tokenizer" , "standard" ) . putArray ( "index.analysis.analyzer.index_words.filter" , "standard" , "word_filter" , "lowercase" , "stop" , "asciifolding" , "porter_stem" ) . put ( "index.analysis.analyzer.search_words.type" , "custom" ) . put ( "index.analysis.analyzer.search_words.tokenizer" , "standard" ) . putArray ( "index.analysis.analyzer.search_words.filter" , "standard" , "lowercase" , "stop" , "asciifolding" , "porter_stem" ) . put ( "index.analysis.filter.gram_filter.type" , "edgeNGram" ) . put ( "index.analysis.filter.gram_filter.min_gram" , 2 ) . put ( "index.analysis.filter.gram_filter.max_gram" , 15 ) . putArray ( "index.analysis.filter.gram_filter.token_chars" , "letter" , "digit" , "punctuation" , "symbol" ) . put ( "index.analysis.filter.word_filter.type" , "word_delimiter" ) . put ( "index.analysis.filter.word_filter.generate_word_parts" , true ) . put ( "index.analysis.filter.word_filter.catenate_words" , true ) . put ( "index.analysis.filter.word_filter.catenate_numbers" , true ) . put ( "index.analysis.filter.word_filter.catenate_all" , true ) . put ( "index.analysis.filter.word_filter.split_on_case_change" , true ) . put ( "index.analysis.filter.word_filter.preserve_original" , true ) . put ( "index.analysis.filter.word_filter.split_on_numerics" , true ) . put ( "index.analysis.filter.word_filter.stem_english_possessive" , true ) . put ( "index.analysis.analyzer.path_analyzer.type" , "custom" ) . put ( "index.analysis.analyzer.path_analyzer.tokenizer" , "path_hierarchy" ) . put ( "index.analysis.tokenizer.dot_tokenizer.type" , "pattern" ) . put ( "index.analysis.tokenizer.dot_tokenizer.pattern" , "\\." ) . put ( "index.analysis.analyzer.uuid_analyzer.type" , "custom" ) . putArray ( "index.analysis.analyzer.uuid_analyzer.filter" , "trim" ) . put ( "index.analysis.analyzer.uuid_analyzer.tokenizer" , "dot_tokenizer" ) ;